1. Technical Field
The present invention relates to a piezoelectric element, a piezoelectric actuator, a liquid ejecting head, a liquid ejecting apparatus, and a method for producing such a piezoelectric element.
2. Related Art
A piezoelectric element includes a structure in which a piezoelectric material is sandwiched between two electrodes. Since a piezoelectric element includes such a structure, deformation of the piezoelectric element such as expansion and contraction can be caused by the application of an electric field to the piezoelectric material. A typical material of a piezoelectric material is lead zirconate titanate or the like.
A piezoelectric element is used as a piezoelectric actuator for a liquid ejecting head or the like. The performance of a piezoelectric element can be degraded by degradation of a piezoelectric material. When a piezoelectric material is an oxide such as lead zirconate titanate, the contact between water and the piezoelectric material causes, for example, an increase in leakage current generated between two electrodes, resulting in degradation of the reliability of the piezoelectric element.
To suppress the contact between a piezoelectric material and water, the piezoelectric material is covered with a barrier film. JP-A-2005-119199 discloses a liquid ejecting head having a structure in which a piezoelectric material is covered with an insulation film. In addition, JP-A-2005-088441 discloses a liquid ejecting head in which a piezoelectric material is covered with an electrode and the electrode is made to function also as a barrier film to suppress the contact between the piezoelectric material and water.